THIS INVENTION relates to the sampling of molten metals and more particularly to sampling such metals effected by immersion of a sampler into metals of both high and low temperatures.
Molten metal sampling using a long handled spoon dipped into molten metal has many disadvantages and has today been largely replaced by methods resulting in a sample of metal being obtained which is disc-shaped to provide a polished surface for spectrographic analysis, usually this sample is obtained along with what is known as a "classic" pin extending from the disc-shaped portion. Such a sample is obtained by dipping a mould consisting of a glass tube engaged in the inlet to a split metal mould into the melt. Molten metal is thereby caused to flow into the mould to fill it and the glass tube. The metal thus contained is removed and freezes in the mould and glass tube.
In order to immerse the mould it is usually held in the end of a thick walled cardboard tube surrounded by moulded sand. The mould is glued in position.
The cardboard tube is, in use, carried by a steel immersion lance which is protected by the cardboard.
A thin metal cap is located over the inlet end to the glass tube to enable the sampler to penetrate through the slag on top of the molten metal.
This type of sampler has certain inherent disadvantages which include the fact that the cardboard tube causes a reaction in contact with molten metal. This reaction can be violent and even dangerous. Resulting from this the sampler can generally only be immersed for a short period and to a limited depth into the molten metal bath.
Added to this is the further fact that there is frequently considerable difficulty in recovering the sample from the cardboard tube on removal from the molten metal.
It is the object of the present invention to provide a method and means for sampling hot metals which at least reduces the above difficulties.